Very simple app is to check the operation of the button. Press the button to display the key codes and actions.
Back button, the other app, since they quit, If this app can be tested.
Long tap, Copy to Clipbord. Press exit to exit. Home button, key code can not detect. The android OS limitation.
If you have selected the EditText at the top, the key code is not detected occasionally.\nPlease try to select this TextView in that case.
Recommended for those who like: Before repair, diagnose it yourself back,menu,volume etc.. Hard Ware button test bluetooth keyboard, USB keyboard, Software keyboard Operation check take root, not easily take to repair
for Developer keycode test key code and KeyEvent.toString() output to logcat this app use dispatchKeyEvent() want to know the key code, at adb shell input keyevent